ACTIVITY ASSOCIATED WITH CORONAL MASS EJECTIONS AT SOLAR MINIMUM - SMM OBSERVATIONS FROM 1984-1986

We have examined 73 coronal mass ejections observed by the coronagraph aboard NASA's Solar Maximum Mission between 1984-1986. The goal of this study was to determine the distribution of various forms of solar activity that were spatially and temporally associated with mass ejections during solar minimum phase. For each coronal mass ejection a speed could be measured, hence, we were able to estimate a departure time of the transient from the lower corona. We then searched for other forms of solar activity that appeared within 45-degrees longitude and 30-degrees latitude of the mass ejection and within +/- 90 minutes of its extrapolated departure time. We present the statistical results of the analysis of these 73 mass ejections, and we found that slightly less than half of the mass ejections had associations. This fraction is lower than reported by similar previous studies of Skylab and SMM 1980 coronagraph observations. We attribute the lower association rate to the large fraction of slow mass ejections detected during 1984-1986. Taken as a group, the slow mass ejections were infrequently associated with other forms of solar activity. This is the first such study to examine the association problem near the minimum phase of solar activity, but our results indicate that the distribution of the various forms of activity related to mass ejections does not appear to change at different phases of the solar cycle. For those CMEs with associations we found that eruptive prominences and soft X-ray events (especially long-decay events) were the most likely forms of activity to accompany the appearance of mass ejections. Our result strengthens the interpretation that most coronal mass ejections are the result of the reconfiguration of a magnetic field structure surrounding a prominence, leading to the destabilization and eruption of the prominence and its overlying coronal structure. This phenomenon occurs in both quiescent prominences and in prominences found in active regions.